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Response time measurement

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sarahlynmart@gmail.com	sarahlynmart@gmail.com posted 7 Years Ago Topic Details Share Topic
Group: Forum Members Posts: 12, Visits: 52	Hello, I want to measure participants' reaction time in response to stimulus onset. I currently have /beginresponsetime written into the code, and while it does measure reaction time, there is no longer a fixation cross presented after each stimulus' trial (the triangle stimulus just goes into the next stimulus without a fixation cross separating each trial). I have copied/pasted the triangle trial below so you can give me suggestions on how to measure reaction time AND keep the fixation cross. Thank you. <trial triangle> / ontrialbegin = [values.category = "triangle"] / ontrialbegin = [values.itemnumber = list.triangleitems.nextvalue] stimulustimes = [0 = fixationcross; 500 = triangle; 1200 = shape.eraser; 1201 = fixationcross] /stimulustimes = [0 = triangle; 1500 = shape.eraser; 1501 = fixationcross] /inputdevice = keyboard / isvalidresponse = [values.responsekey] iscorrectresponse = [values.responsekey = 1] / beginresponsetime = 0 / timeout = (values.fixationduration + values.trianglepresentation) / posttrialpause = rand(values.iti_min, values.iti_max) </trial>
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Dave	Dave posted 7 Years Ago ANSWER Post Details Share Post
Group: Administrators Posts: 12K, Visits: 98K	+x sarahlynmart@gmail.com - Tuesday, January 3, 2017 Hello, I want to measure participants' reaction time in response to stimulus onset. I currently have /beginresponsetime written into the code, and while it does measure reaction time, there is no longer a fixation cross presented after each stimulus' trial (the triangle stimulus just goes into the next stimulus without a fixation cross separating each trial). I have copied/pasted the triangle trial below so you can give me suggestions on how to measure reaction time AND keep the fixation cross. Thank you. <trial triangle> / ontrialbegin = [values.category = "triangle"] / ontrialbegin = [values.itemnumber = list.triangleitems.nextvalue] stimulustimes = [0 = fixationcross; 500 = triangle; 1200 = shape.eraser; 1201 = fixationcross] /stimulustimes = [0 = triangle; 1500 = shape.eraser; 1501 = fixationcross] /inputdevice = keyboard / isvalidresponse = [values.responsekey] iscorrectresponse = [values.responsekey = 1] / beginresponsetime = 0 / timeout = (values.fixationduration + values.trianglepresentation) / posttrialpause = rand(values.iti_min, values.iti_max) </trial> A <trial>'s default behavior is to terminate / go to the /posttrialpause as soon as a response has occurred. You can modify this behavior via the /responseinterrupt attribute. In your case, you'll probably want to set it to 'frames': https://www.millisecond.com/support/docs/v5/html/language/attributes/responseinterrupt.htm Note, too, that by default stimuli will be erased when the trial terminates / during /posttrialpause. You can modify this behavior by setting the respective stimulus elements' /erase attributes to 'false'. https://www.millisecond.com/support/docs/v5/html/language/attributes/erase.htm Also see http://www.millisecond.com/support/docs/v5/html/howto/howtoerase.htm for an explanation of the erasing behavior. Beyond that, there are a couple of issues with the <trial> code you posted. (1) You may not have multiple /stimulustimes attributes in a given <trial>, only one. I'm not sure whether one of them is just a remnant of previous edits or if you intend both to work. (2) Both the /isvalidresponse and /iscorrectresponse attributes are not functional in their current state. Here, too, I'm not sure whether that just reflects an early state of development or a genuine mistake. Edited 7 Years Ago by Dave
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